The mirror, the map and the photograph have all at one time or another served as emblems of the yearning for a representation so faithful and so complete that it can’t be distinguished from what it represents. Of the three, the map might appear to be the odd one out: the mirror and the photo may be two-dimensional illusions of a three-dimensional reality, and both are notoriously prone to distortion, but they operate by optical mechanisms that apparently guarantee a slavish fidelity to what can be seen. The map, in contrast, must select, symbolise, abstract and contract the reality it represents. There may well be artistry in the creation of mirror-images and photos, and in ways of interpreting them, but maps require making and reading in a more obvious way. One has only to be confronted by a map that employs unfamiliar conventions – for example, Leonardo da Vinci’s sketch (1502-03) of a plan to regulate the River Arno, or the world portrayed according to the currently controversial Peters projection (in which southern continents appear considerably larger than they do in the familiar Mercator projection) – to realise how much maps depend on conventions for their intelligibility and utility. All conventions have their history, their rules of legibility, their implicit and explicit biases about what is significant and what negligible, just as languages do. Not all languages develop a refined vocabulary for colours: not all maps record the locations of parish churches or the manor houses of the gentry. Conventions are the precondition for parody, and maps lend themselves as happily to spoof as any literary genre – perhaps even more effectively, since the visual elements of caricature can be enlisted along with words. Saul Steinberg’s map of the world according to New Yorkers (in which Manhattan looms large, and everything west of the Hudson fades into unsignposted insignificance) neatly makes the point about maps being rooted in their cultures.

Why, then, has so much fuss been made about the ‘new geography’, and its claim to reveal that maps are texts to be read, recognisable products of the historical context in which they were made? The fuss is real enough: the editor of this posthumous collection of essays by J.B. Harley, bellwether of the new geography, took the unusual precaution of including a critical introduction by J.H. Andrews, for fear that Harley’s approach might become ‘an unquestioned orthodoxy or worse, a catechism’. Just what that approach was defies easy summary because it hybridised so many diverse elements. Panofsky, Marx, Cassirer, Derrida, Foucault, Barthes, Gombrich and Kuhn would no doubt have been astonished (and perhaps appalled) to be invoked in the same essay, sometimes even in the same sentence. But it was probably less this motley pantheon of authorities than Harley’s gift for provocative aphorisms – e.g. ‘Maps are pre-eminently a language of power, not protest’ – that won him an avid audience in and beyond the history of cartography.

In his survey of the way images of the terrestrial globe have been shaped and in turn have shaped Western notions of the Earth and of humanity, Denis Cosgrove is less preoccupied by the notion of maps as ‘power-techniques’ but he, too, is alert to the subtle and not so subtle ways maps and globes send messages and serve interests. From the heart-shaped projections favoured by 16th-century religious reformers for their associations with brotherly love to the Van der Grinten projection which exaggerates the size of the temperate at the expense of the tropical zones and was long preferred by the National Geographic magazine, even the most technical aspects of mapmaking take on an ideological cast. The new geography has given maps more than textuality and contextuality: it has given them politics.